Why This Report Matters. Air quality policy in Canada is at a crossroads. Decades of regulation have successfully cut industrial and combustion-related PM2.5, but those gains are increasingly erased by wildfires and urbanization-driven dust. Decision-makers in public health, urban planning, and climate adaptation need to understand which sources are improving, which are worsening, and where the next crisis will come from. This report translates 34 years of federal emissions data into actionable patterns: where to double down on regulation, where to invest in monitoring, and why wildfire smoke policy is now a public health emergency.

Chapter 1 · Background. This report explores three decades of Canada’s fight against fine particulate matter - the most dangerous common air pollutant. Using national inventory data, provincial reports, and city-level monitoring, it asks three questions:

Fine particulate matter (PM2.5) refers to particles smaller than 2.5 micrometres, about 30 times smaller than a human hair. Unlike larger particles that your nose and throat filter out, PM2.5 bypasses your lungs and enters your bloodstream, causing damage far beyond the respiratory system. It is the single largest environmental health risk in Canada.

The data comes from the Air Pollutant Emissions Inventory (APEI) 2025 Report by Environment and Climate Change Canada, which tracks anthropogenic emissions across five PM2.5 source categories. It does not include wildfire emissions in its main totals, a critical distinction explored later.

Chapter 2 · The National Picture. Total anthropogenic PM2.5 fell from roughly 1,609 kt in 1990 to 1,370 kt in 2023 (a 15% decline). But this hides a tug-of-war: industrial and combustion sources have plummeted, while dust from roads and construction has climbed steadily.

Chapter 3 · The COVID Dip. The pandemic gave Canada an unintended natural experiment: road dust dropped 15% as traffic fell, construction slowed, and total emissions hit their lowest in 34 years. By 2023 every category had rebounded or exceeded pre-pandemic levels.

Chapter 4 · Wildfires Dwarf Everything Canada Regulates. The APEI tracks human-caused emissions, but wildfires (excluded from its main totals) can dwarf anthropogenic sources in a single season. Using emission factors from ECCC and UNDRR research (~713 kt PM2.5 per million hectares burned), the 2023 wildfire season produced roughly 10,700 kt of PM2.5 — nearly 8 times Canada’s entire annual anthropogenic total.

Chapter 5 · Same Country, Very Different Air. National averages hide enormous variation between cities. In a normal year, most Canadian cities sit below the CAAQS standard of 8.8 µg/m³. But 2023 was not a normal year. Edmonton hit 16.6 µg/m³ — nearly double the limit. The 2023 IQAir World Air Quality Report found Canada was the most polluted country in North America for the first time.

Chapter 6 · The Biggest Threat Isn’t Industrial. Canada has steadily cut PM2.5 from regulated sources. But wildfires are increasingly undoing that progress. The 2023 season burned over 14 million hectares, the most since 1970. National average PM2.5 concentrations in 2023 were 62% higher than 2009, and peak concentrations 167% higher.

All national emissions data comes from the APEI 2025 Report (1990–2023) by ECCC. Provincial data from Ontario’s Air Quality Report 2023. City-level PM2.5 from NAPS and IQAir. All figures are emissions (tonnes) unless labelled as concentrations (µg/m³).